ByJeb Boone, / CorrespondentJune 12, 2011

Yemeni fighters loyal to rebel tribal leader Sheikh Sadiq al-Ahmar inspected damage to his house in Sanaa on June 7. The powerful Ahmar family has emerged as one of the primary challengers to Saleh's regime.

Sanaa, Yemen — In Yemen's capital, a dusty city of more than 2 million surrounded by rugged mountains, security forces roam the streets to keep a lid on the rebellion after President Ali Abdullah Saleh abruptly left the country.

All along Sanaa's major thoroughfares, they stare down the barrels of Russian DShK heavy machine guns mounted in the back of camouflage-painted pickup trucks. Meanwhile, protesters chant, "Stay away, Ali Saleh!"

Officials insist that the president, who was badly injured in a June 3 attack on his home and went to Saudi Arabia for medical treatment, will return to reassume the post he has held for 32 years. But how long that may take is uncertain. In the interim, an elite power struggle could profoundly shape the future of Yemen.

"There are a lot of people who stand to benefit from continued violence," says Yemeni political analyst Abdul-Ghani al-Iryani. "Saleh's boys won't hesitate to use violence to honor their father and, of course, the political opposition is always looking for a way to keep themselves relevant."

While the major players set their sights on the presidential palace, a small band of armed militants known as Al Qaeda in the Arabian Peninsula (AQAP) is threatening to seize territory in the south. Clashes this weekend reportedly killed 10 soldiers and 21 suspected AQAP militants.

There is an urgent need to establish a clear political order not only for the country's security but also its economy, which a Western diplomat here says is set to collapse by August amid shortages of basic supplies and soaring prices.

Even before Yemen's uprising, Mr. Saleh's tenuous grip on disparate tribes was slipping. In 2004, his government began an off again, on again war against Houthi rebels in the north. Meanwhile, Saleh continued his brutal crackdowns on a southern secessionist movement that was gaining momentum.

US officials were increasingly concerned that a local Al Qaeda franchise would find a haven in its hinterlands to plan more attacks against the West, after two major plots were foiled.

All these concerns have been exacerbated by a popular uprising that turned violent last month as tribesmen began fighting Saleh loyalists in the capital. On June 3, amid pitched battles in the capital – the most violent in half a century – the presidential compound was attacked during Friday prayers.

Now the man who has held this volatile country together for decades is convales­cing in Saudi Arabia, his political future – and likewise Yemen's – uncertain.

Since coming to power in 1978, Saleh has spent blood and treasure to placate his rivals. But now they have coalesced around the youth protesters, presenting a more unified challenge.

"We are all one in demanding that Saleh leave power," says Nuha Jamal, a youth activist in the southern port city of Aden. "All of Yemen is united in this cause."

A game of thrones ensues

As Saleh left Yemen, many pro-­democracy protesters celebrated through the night with fireworks. But even as Vice President Abd Rabo Mansur Hadi was named acting president, a game of thrones was taking shape that threatened to sideline the interests of the protesters – the very people whose uprising had precipitated Saleh's departure.

"Our revolution was hijacked by the tribes," said Shatha al-Harazi, a young Yemeni activist. "How can we establish a civil state if tribes still wield so much power?"

Along with the vice president, several groups stand to gain everything in the ensuing chaos of Saleh's departure. Tribal rebels, loyal to the powerful Ahmar family and defected Gen. Ali Mohsen al-­Ahmar (no relation), pose an armed threat to the president. The political opposition known as the Joint Meeting Parties (JMP) is looking to cement its position in a new Yemeni government and is doing so largely on the backs of protesters who have vowed to remain in their camps until a new president is elected.

While Vice President Hadi has technically assumed presidential powers, it is Saleh's son Ahmed and his eldest nephew, Yahya, who are acting as the president's proxies. They command the Republican Guard and the Central Security Forces, respectively, keeping a firm hold over the capital and continuing the fight against armed rebel tribesmen.

The vice president remains holed up in his home near the protest camp's borders, while tribesmen and loyalists fight less than two miles away. Led by the prominent Ahmar family, the tribal fighters have withstood more than two weeks of constant shelling.

Many see the ambitious Hamid al-­Ahmar as fomenting unrest for his own benefit, though he has denied making a bid for power.

"I do not want to be president. The next president of Yemen should be from the south, such as Yaseen Saeed Noman [head of the Yemeni Socialist Party]. Personally, I would vote for him," said Mr. Ahmar in an interview before the violence broke out last month. However, as a member of the opposition Islah party, he may be hedging his bets by having dogs in two fights.

Islah is part of the JMP coalition, which is pushing for a transitional council and presidential elections – a plan taken from a Gulf-brokered power deal that Saleh has reneged on three times. The JMP is a signatory to the plan, which guarantees its position in a new Yemeni government and has the potential to grant it even greater power if a member of the JMP is elected president.

Disunity without Saleh as shared enemy?

However, the JMP – a tenuous union of Islamists, cold-war-era socialists, and Arab nationalists – may fracture without the figure of Saleh as a common enemy.

JMP spokesman Mohammed Qahtan has vowed to do everything in his power to keep Saleh from returning to Yemen. But without the military might to shut down the airport, the JMP may have little chance of fulfilling its goals at keeping Saleh in Saudi Arabia.

The two men who stand in the JMP's way, Yahya and Ahmed, have the entire loyalist military to roll out a red carpet for Saleh's return.

In fact, all of Yemen's disparate groups struggling to achieve their own goals for a new Yemen will have to contend with these two men. Should Saleh return from Saudi Arabia, which he is expected to eventually do, Yahya and Ahmed have the strength to facilitate his homecoming. If Saleh remains in Saudi Arabia, his son may succeed him in the presidential palace, where he has already taken up residence.

But if protesters, political rivals, or defected generals attempt to implement their idea of a new Yemen, at least one Saleh – be it Ahmed or Ali – will probably stand in their way.